Electronic commerce is a popular way of selling products, services and other items to consumers. A typical electronic commerce system may provide user interfaces that enable consumers to browse and/or purchase items from a merchant or seller associated with the electronic commerce system. Electronic systems that support user-to-user sales of items have also become popular. Sellers in such systems typically include both small merchants and non-merchant individuals. Item listings can typically be located using a search engine. In some cases, the user-to-user sales system is operated in association with a network-based retail store such that a customer can search a retail catalog, as well as a database of item listings from users, via a single search query.
Different sellers in an electronic marketplace will often use very different terminology to describe identical items. As a result, buyers seeking certain items often fail to find relevant listings. Further, small sellers sometimes fail to fully and accurately describe their items, resulting in lost sales and/or erroneous purchases. Some user-to-user sales systems seek to address such problems by allowing a seller to specify a Universal Product Code or other item identifier of an item being listed. This allows the system to associate different sellers' listings for a particular item. However, various problems may be encountered when a system attempts to match newly submitted item information from a seller with an existing item listed in an electronic catalog. For example, a seller may associate the seller's own internal item codes with items that the seller lists for sale, rather than a more universally known item identifier, or may incorrectly enter certain item information.